Governor for one shot gyro



D. BLITZ Dec. 22, 1964 GOVERNOR FOR ONE SHOT GYRO 5 Sheets-Sheet 1 Filed May 10, 1961 Fig.

Daniel Blitz IN VEN TOR ATTORNEY Dec. 22, 1964 D. BLITZ 3,162,053

GOVERNOR FOR ONE SHOT GYRO Filed May 10, 1961 5 Sheets-Sheet 2 MAXIMUM SPEED MINUTES Fig.2

MAXIMUM SPEED eovenuso D SPEED c SPEED MINIMUM A- USEFUL SPEED -M|LLlSECONDS-*I h MINUTES TIME Fig.3

A T TORNE Y D. BLITZ Dec. 22, 1964 GOVERNOR FOR ONE SHOT GYRO 5 Sheets-Sheet 3 Filed May 10, 1961 Daniel Blitz INVEN TOR %M&W%

AT TORNE Y D. BLITZ Dec. 22, 1964 GOVERNOR FOR ONE SHOT GYRO 5 Sheets-Sheet 4 Filed May 10, 1961 Fig.9

Daniel Blitz INVENTOR ATTORNEY g aw Fig.|O

Dec. 22, 1964 Filed May 10, 1961 5 Sheets-Sheet 5 2 44 \H Irf 5| 4s 46 3 49 Fig. ll

65 7 12 r\' I x s3 15 e2 Fig.l2

Daniel Blitz INVENTOR ATTORNEY v United States Fatent Gd 3,l62,5 3 Patented Dec. 22, 1964 3,162,053 GGVERNGR FGR ()NE SHOT GYRQ Daniel Blitz, Boston, Mass, assignor to Sanders Associates, Ind, Nashua, NEE, a corporation of Delaware Filed May 10, 1% Ser. No. IIEJGS 4 (Ilaims. (El. Wt-5.7)

This invention relates generally to a gyroscope employed in modern guidance instruments, guided missiles, and the like. More particularly, this invention is directed to fluid pressure actuated gyroscopes that have the gyro rotor speed governed by a speed responsive unit which controls the rate of fluid pressure release in the gyro rotor drive system. While the invention is subject to a wide range of applications, it is especially suited for use in missile guidance systems and will be particularly described in that connection.

In modern guidance systems of a single operational use variety, such as built into guided missiles, the need for providing simple, inexpensive, and yet highly reliable components is readily apparent. More particularly, missiles intended for short-range operation are produced in large quantities. Hence, the cost of such missiles and components should be minimized. Furthermore, for missiles in this category components should be capable of storage for indefinite periods of time, and be capable of becoming operational in an extremely short period of time, and of functioning during the missile flight. A gyroscope intended for use in this type environment thus should be relatively inexpensive, capable of attaining suiticient speeds for providing gyroscopic actionin a short period of time and being stored for periods of time as I long as five years. The gyro rotor rotation must be initiated in a short time, e.g., (0.01 second) and come up to a predetermined speed Within a short time thereafter, e.g., (0.5 second). After reaching a predetermined speed, the rotor speed should be maintained at a useful level for a relatively long period of time, e.g., eight minutes. The gyroscope should be capable of repeated pretesting prior to intended use for checkout purposes Without degrading its operation or contaminating its parts.

Various attempts to solve the above-mentioned prob lems have included gyroscopes which are electrically driven, spring driven, and gyroscopes driven by the products of combustion of explosive charge. An electrically driven gyroscope is relatively high in cost and very complex in nature. This type of gyroscope is usually carried in a running condition so as to be at speed prior to firing of the missile. The explosive type of gyroscope on the other hand, although less expensive to manufacture than the electrically driven gyroscope, has serious drawbacks in performance. Upon releasing the explosive charge, there is a tendency to contaminate the gyroscope components with the explosive residue, thus impairing the gyrocopes performance. In addition, this type of gyroscope cannot be pre-test fired so that performance characteristics can be actually predicted prior to the gyroscopes operational use. On the other hand, while spring driven units do not have any of the undesirable characteristics of either the electrically driven or explosive type gyroscopes, they do have a serious drawback in reliability. Under high inertial accelerations as encountered in most advanced guided missiles the performance of the spring driven gyroscope has a tendency to degrade.

In general, the gyroscope of the present invention is a self-contained unit. A fluid under pressure is stored within the gyroscope housing and a hollow rotor element. In operation, the fluid is released to the atmosphere and flows through nozzles in the hollow rotor. The reaction of the fluid how on the rotor causes the rotor to accelerate. After the rotor accelerates to a predetermined governed speed, a caging mechanism releases a gimbal allowing the gyroscope instrument to provide reference direction signals. Simultaneously with the rotor acceleration, a centrifugal force responsive governor controls the effective size of the rotor nozzles and thereby maintains the rotor speed constant over a long period of time, for example, eight minutes.

It is therefore an object of the invention to provide an improved gyroscope capable of reaching a predetermined governed speed in a relatively short period of time.

It is a further object to provide a gyroscope with simplified construction for economical manufacture.

Furthermore, it is an object of the invention to provide a gyroscope that is actuated after the time of missile launching.

It is a further object of the invention to provide a gyroscope free of contamination in operation.

It is a further object of the invention to provide a gyroscope that is readily pretestable before firing.

It is a further object of the invention to provide a gyroscope that is reliable in operation and performance.

It is a further object of this invention to provide an air driven gyro rotor with the rotor speed control mechanism.

It is still a further object of this invention to provide a variable rotor nozzle to control the'rate of fluid pressure through the nozzle and therefore control the rotor speed.

It is another object of this invention to provide a centrifugal force responsive nozzle opening control.

It is another object of this invention to provide a con stant speed pressure driven gyro rotor.

For a better understanding of the present invention,

together with other and further objects thereof, reference is made to the following description taken in connection with the accompanying drawings and its scope will be pointed out in the appended claims.

FIGURE 1 is a schematic drawing illustrating a gyroscope made in accordance with the present invention.

FIGURE 2 is a graphof rotor speed vs. time for a gyroscope not embodying the present invention.

FIGURE 3 is a graph of rotor speed vs. time for a gyroscope embodying the present invention.

FIGURE 4 is a side elevation partly in section of a preferred embodiment of a gyroscope made in accordance with the present invention.

FIGURE 5 is a plan view partly in section of a" gyroscope shown in FIGURE 4 with its cover removed and its speedresponsive mechanism shown in section.

FIGURE 6 is a partial section taken of the gyro rotor with the speed responsive unit in an unactuated position.

FIGURE 7 is a partial section taken of the gyro rotor with the speed responsive unit in an intermediate position.

FIGURE 8 is a partial section taken of the gyro rotor with thespeed responsive unit in a fully actuated position.

FIGURE 9 is a sectional view of a charging valve taken along the line 9% in FIGURE 5.

' FIGURE 10 is a sectional view of a release mechanism taken along the line Iii-Jilin FIGURE 5.

FIGURE 11 is a sectional elevational View of the gyroscope of FIGURE 4 taken along the line 11-11 in FIGURE 5.

FIGURE 12 is a sectional view of the caging mechtaken along the line 12I2 in FIGURE 5.

Principles of Operation The gyroscope of the present invention has as one of its unique features a potential energy source stored within a hollow rotor, although many energy sources may be stored in a rotor such as chemical, nuclear, mechanical, electrical magnetic, etc., in the preferred embodiment, a compressible fluid is stored within the rotor as a potential energy source.

orifices in the rotor 21 to a hollowchamber within the rotor. After filling,'the gyroscope is sealed for storage.

To initiate rotor rotation, the release mechanism 24 is energized. Energization of release mechanism 24 causes a large opening to be made in housingztl. The opening of the housing enables fluid to flow from the interior of the housing to the atmosphere. The fluid flow causes a drop in pressure in the area surrounding the rotor and thus produces a differential pressure across the rotor walls. The differential pressure between the rotor interior and the housing enables fluid to flow from the interior of the rotor through orifices communicating with the rotor and the housing as shown by arrows D in FIGURE 1. The latter fluid flow being restricted occurs at a slower rate thanthe fluid flowing through the release mechanism 24. The reaction of the fluid flowing through the orifices causes rotor 21 to be accelerated in the direction shown by the arrows E in FIGURE 1. While the rotor is being accelerated, the gimbals and the rotor are maintained in a fixed position by a caging mechanism 25. When the rotor reaches a predetermined speed, the caging mechanism is released and the gyroscope operates to furnish position indication signals in the conventional manner.

Referring now to FIGURE 2 of the drawing, there is shown a typical curve of rotor speed vs. time for a gyroscope that does not embody the present invention. As can be seen in FIGURE 2 the rotor reaches a maximum speed in a relatively short period of time, for example, 500 milliseconds and is uncaged. The rotor continues to rotate at a suflicient speed to provide gyroscopic action for a relatively long period of time, for example, eight minutes. It may also readily be seen that the gyro can be used as a reference any time the speed is above the minimum useful rpm. point but it should be noted that the speed is constantly decreasing and the gyros response to a disturbing force during this time is constantly changing. This constantly varying signal of necessity requires a complex electronic system to interpret the information and provide usable reference signals for navigational purposes. Moreover, with the characteristics shown in FIG- URE 2, a gyrorotor and its bearings must be of a very rugged construction in order to accommodate the large acceleration forces and high speed imposed on them. It is this combination of factors that brought about the invention here involved.

Referring now to FIGURE 3 of the drawings, there is shown a typical curve of rotor speed vs. time for a gyroscope that embodies the present invention. This figure shows behavior of a gyro of the same type as in FIGURE 2 but fitted with a centrifugal governor of the type utilized in the present invention. As will be noted, when the gyro is actuated there is a rapid" acceleration from standstill point A, FIGURE 3 pass the minimum useful rpm. point B to the speed at which the governor begins to operate, point C. The gyro continues to accelerate but the rate of acceleration is decreased and the gyro rotor speed settles out at the governed speed D at about the same time that the ungoverncd gyro in FIGURE 2 took to reach the maximum speed. Once governed speed is reached, this speed is maintained until the compressed gas power supply is exhausted. This will take place in about 8 to 9 minutes after the governed speed is reached, that is point B on the curve of FIGURE 3, and the gyro will then coast until the minimum useful r.p.rn. point is reached; that is point P in FIGURE 3. Note that since the speed is constant for such a long period of of time the response to outside forces will also be constant and the control circuits using these gyros as a reference will have a more consistent response than with the free gyro depicted graphically in the response curves of FIG- URE 2. It is instantly apparent that in view of the fact that the gyro need not be accelerated to a point as great as that depicted by FIGURE 2, the entire mechanism which would be constructed to function in the manner shown in FIGURE 3, would not have to be of as heavy a construction because the gyro rotor and its respective bearings would not have to sustain the above noted high accelerations and accompanying forces.

Detailed Description Referring now in more detail to the drawings and with particular reference to FIGURE 4, there is here illustrated a side elevation partly in section of a preferred embodiment of a gyroscope made in accordance with the present invention. The gyroscope is contained within the housing 2% of general spherical shape. As can be seen in FIGURE 4, the housing 20 includes an upper half 29a, threadedly connected to a lower half 29!). The distance between the outer periphery of housing 2% and its inner wall is chosen in accordance with the internal fluid pressure the housing will have to withstand and the particular material selected for fabricating the housing. In the preferred embodiment, the housing material is an aluminum alloy but a wide variety of alternate material such as steel, brass, or magnesium alloy may also be utilized.

Referring now to FIGURE 5, there is here illustrated a plan view partly in section of the gyroscope shown in FIGURE 4 with its cover removed. As shown in FIG- URE 5, the housing 20 is provided with a charging valve 23 mounted in its wall. Charging valve 2.: enables the gyroscope to be filled with fluid under pressure. The gyroscope'housing is shown with the release mechanism 24 mounted in its wall. The release mechanism is provided for releasing the fluid under pressure stored within the gyroscope to a low pressure area for example, the atmosphere. A hollow rotor 21 is supported in the gyro housing 26 by the gimbals 22a and 22b for rotation about an axis of spin. Rotor bearings 47 and 48 (FIGURE 11) have flange ends (not shown) and are connected to an inner gimbal ring 49 by screws 51 The inner gimbal ring 4? is pivotally coupled to an outer gimbal ring Sll by diametrically opposed bearings and pins 52. The center lines of the bearing and pin assembly are lined so as to allow pivotal motion of the inner gimbal about an axis perpendicular to the axis of spin. The outer gimbal ring 51 is pivotally coupled to housing 29 by diametrically opposed bearing pins 53 and bearings 54. The center lines of the outer gimbal bearings are oriented perpendicularly to the inner gimbal bearing center line and the axis of spin. While the invention has herein above been described in terms of a two-degree of freedom gyro the invention is also capable of being applied to a single degree of freedom gyroscope. For example, by eliminating the outer gimbal and its associated bearings and bearing pins and pivotally mounting the inner gimbal ring 49 to the housing, the gyroscope shown in the drawings will be a single-degree of freedom gyroscope.

Referring again to FIGURE 5, one of the unique features of this invention is directed to the means of accelerating the rotor 21. Referring specifically to FIG- URE 5, rotor 21 is seen to be provided with impeller means in the form of passageways 55 and orifices 52 communicating with the interior and exterior chambers of the rotor.

In operation, the fluid flowing from these orhices causes the rotor to rotate about its axis of spin. In the preferred embodiment, the rotor has two diametrically opposed orifices 56 communicating with the housing and the rotor interior chambers 5'7 through fluid passageways 55 respectively. The orifices 56 are diametrically opposed with their exits oriented in opposite directions as shown. The orifices are disposed so that the maximum torque is imparted by the rotor by reaction of the fluid going through the orifices. Although any number of orifices may he used it is preferred to use even number of diametrically opposed orifices to minimize the loading of the bearings 47 and 48. The internal diameter and shape of the orifices of passageways are of critical importance and are determined by the internal pressure within the rotor cavity 57, the desired rate of fluid flow, and the desired rotor speed.

In regard to the desired rotor speed, there will be noted by referring to FIGURES 6, 7 and 8, which show in detail a cross section of the orifices of rotor 21 namely orifice 56 and relief port 55, a variable cantilever mounted spring 106 with its associated member 102 disposed and connected to the spring 190 at right angles.

Referring now to FIGURE 9, there is here illustrated an enlarged sectional view of the charging valve 23 taken along line 9-9 in FIGURE 5. As can be seen in FIG- URE 9, the charging valve includes a valve casing 26 of general cylindrical shape. The valve casing has an opening therein for communicating with a fluid pressure filling apparatus. After filling, sealing of the charging valve is provided by a ball seal 27 mounted on a spring 28. Spring 28 is retained in the valve casing 26 by a circular rim 29 which extends into a central opening 31' in the valve casing 26. There are thus provided filling means in the housing 20 enabling filling of the housing with fluid under pressure in the form of a valve casing 26 having an aperture 3%? therein. In addition, means for sealing the charging valve to retain the fluid under pressure are thus provided in the form of circular rim 29, spring 28, and ball seal 27.

Referring now to FIGURE 10, an enlarged section view of the release mechanism taken along the line 1il in FIGURE 5 is shown. As can be seen in FIGURE 18, the housing 26 has a circular boss 31 extending from its outer periphery. The circular boss 31 has an aperture 32 therein substantially as shown. The interior of the wall formed by aperture 32 and circular boss 31 is internally threaded as shown at 33. A retainer 34 of general cylindrical shape is threaded to circular boss 31 as shown in 33. A cylindrical flange collar 35 having an outer diameter substantially equal to the internal diameter of retainer 34 is supported by the retainer 34 on its flanges as shown. Collar 35 has circular openings 36 therein for allowing the fluid under pressure to flow from the interior of the housing of the atmosphere during operation. A piston seal 37 is disposed within the retainer 34 and has an O ring seal 38 around this periphery for sealing the fluid under pressure within the housing. Piston seal 37 is coupled to and supported by collar 35 by means of a fusible link 39. The fusible link 39 is threadably connected to piston seal 35 and soldered to collar 35. An electrical conductor 39 is connected to fusible link 39 and an external source not shown. An electrical current passing through conductor 39 causes fusible link 38 to melt allowing the piston seal 35 to be released due to pressure forces acting on its face, thus providing a release means for releasing the potential energy stored in the housing. After release, piston seal 37 is retained in a basket like structure 40 welded to retainer 34. The cross sectional area of the openings 36, apertures 32 and the openings in the basket structure 48 are determined bythe internal pressure of the fluid and the time desired to allow the pressure within the housing to drop.

A detailed section taken along the line 11-11, FIG- URE 5 is shown in FIGURE 11.

Referring now to FIGURE 11, rotor 21 includes an annular ring 41 for providing the inertia necessary for gyroscopic action. The annular ring 41 has an outer periphery of general spherical shape and is preferably made of an aluminum alloy. Alternate materials, such as brass, steel, tungsten alloys may also be employed. Two parallel circular plates 42 and 43 are welded toannular ring 41 along its edges. These plates lie in parallel planes perpendicular to the axis of revolution of the annular ring 41. In operation, annular ring41 is rotatable about its axis of revolution. The axis of revolution of annular ring 41 will hereinafter be referred to as the axis of spin. Coupled to the plates 42 and 43 is a hollow rotor shaft 44 having a center line coincident with the axis of spin. Bearing pins 45 and 46 are coupled to shaft 44 by means of an interference fit. In addition, bearing pins 45 and 46 are pivotally mounted in the rotor bearings 47 and 48 to permit rotation of the annular ring 41 about the axis of spin.

In order for signals furnished by the gyroscope to be useful, there must be references to fixed axis. Therefore, the axis of spin, and the gimbals are kept in a fixed position during storage and acceleration. This locking of the components is commonly referred to as caging.

Referring now to FIGURE 5, there is shown a caging mechanism 25 mounted on the gyroscope housing 26.

Referring now to FIGURE 12, a sectional view of the caging mechanism taken along line 12-12 in FIGURE 5 is shown. In FIGURE 12, the caging mechanism is shown in the caged position. The caging mechanism includes the locking piston 61 which is coupled to inner gimbal 4% and outer gimbal 51 through apertures 62 and 63 respectively. A fluid passageway 64 in locking piston 61 coupled the housing chamber to a pressure chamber 65. A second movable piston 66 holds locking piston 61 in apertures 62 and 63 while the gyroscope is being pressurized. Piston 66 has a fiuid passageway 67 therein coupling piston area 69 with the atmosphere. Passage 67, therefore, provides a differential pressure between piston areas 68 and 69. A resilient spring 70 and cavity 71 provides a bias force for the locking piston 61. An indicating switch 72 is mounted in cover 73 which in turn is threadably connected to'the housing 16. Switch 72 is preferably an on-off switch and indicates whether the gyroscope is in the caged or uncaged condition. The switch further cooperates with the caging mechanism to indicate whether or not the pressure in the housing is above a predetermined safe level for operation. 0 ring seals 74, 75, 7 6 and 77 prevent fluid from escaping through the caging mechanism to the atmosphere of a gyroscope is in storage. The operation of the caging mechanism will be described hereinafter.

Other parts of the gyroscope such as the pickoff means for each degree of freedom of movement are not shown. The presence of these parts in the drawing is not required for an understanding of the invention. In the preferred embodiment of the gyroscope two sets of the pickolf elements are provided. One set indicates position of the inner gimbal relative to the outer gimbal and another set indicates the position of outer gimbal relative to the housing 20. Although the pickolf will be described hereinafter in terms of a potentiometer other types of transducers could also be used. The resistance element of one of the potentiometers is preferably circular and mounted on the outer gimbal. The contact arm is mounted on the inner gimbal thus relative movement of the inner gimbal to the outer gimbal will produce a voltage proportional to a fixed reference. The resistance element of the outer gimbal pickoff is mounted on the housing and the contact arm on the outer gimbal producing a voltage proportional to the outer gimbal position relative to the housing. An electrical connection is provided for picking off signals for the potentiometer sets and is aifixed to the housing.

Referring now to FIGURE 5, there will be noted cantilever mounted spring elementslfii), 103, fixed to gyro rotor 21 on the inner surface of the hollow rotor 21. The spring elements 100, 103, may be fixed to the rotor by any suitable connector such as rivets, screws, or weldmg.

In FIGURES 6, 7 and 8 there is depicted a partial section of the gyro rotor 21 and centrifugal force responsive orifice control spring 109, 102. In FIGURE 6, it will be seen that the orifice control spring 190 has integrally formed thereon an orifice control portion 102 disposed at substantially right angles to the main portion 10th FIG- URE 6 depicts the gyro rotor whenthe centrifugal force responsive orifice control spring is in a static condition such as would exist just before gyro rotor actuation, or in the alternative after the gyro rotor has come to a halt after its spin cycle. In this position the orifice baflie element 192 does not afiect the rate of fluid pressure flow through the orifice 56, which pressure how would occur at the instant a pressure diflerential appeared across the orifice 56.

In FIGURE 7, there are depicted the gyro rotor 21 and the orifice control unit 100, H32, in an intermediate position. The rotor initially begins to pick up speed due to the acceleration brought about by the reaction of expanding fluid as it leaves orifice 56. The acceleration produces a centrifugal force which acts upon the spring element 100 which tends to move the spring 190 and its connected bafile element 192 into an intermediate position which restricts the flow of fluid through the orifice 56. This in turn reduces the reaction force created by the expansion of the fluid at the orifice and therefore the speed of the rotor decreases. The selection of the cantilever mounted spring is dependent upon such factors as weight of the spring and the spring constant needed to balance a predetermined centrifugal force which in turn is determined by the governed rotor speed that is sought in the instant application.

Referring now to FIGURE 8, wherein there is depicted the gyro rotor 21 and the orifice controlled unit 1%, 102 in a fully extended position. This situation arises when the gyro rotor 21 has experienced an acceleration that has brought the rotor up to a speed such that the spring cannot overcome the centrifugal force that arises. Here the orifice control unit 106, 102 exerts its maximum control over the speed obtainable by the gyro rotor.

Referring now to FIGURE 4, the assembled gyroscope is filled with a fluid under pressure through the charging valve 23. In the preferred embodiment of the invention, the fluid used is dry nitrogen at a pressure of approximately a thousand pounds per square inch at ambient temperature, five or ten per cent helium may be mixed with the nitrogen for the purpose of performing periodic mass spectrum meter analysis during the storage period. The presence of helium provides a simple, encient and inexpensive method of extrapolating the storage life of the unit.

While we have described the invention as using dry nitrogen, other compressible fluids under pressure may be used for this purpose. The fluid fills the entire cavity within the housing, and within the rotor and thus provides a potential energy means stored within the rotor.

Referring now toFIGURE 10, operation of the gyroscope is started by passing an electrical current, for example, amperes at to 28 volts DC. for approximately 10 milliseconds or less through conductor 38 to fusible length 39. This electrical current causes the length 39 to, melt. The internal pressure acting on the surface of the piston seal 37 causes the member to be released into the basket 40. The fluid under pressure rushes through the relatively large opening 36 to the at mosphere. The sudden drop in pressure in the housing creates a differential pressure between the housing and the rotor cavity causing fluid to flow through the nozzles in the rotor. The reaction of the fluid flow on the rotor causes a torque to appear and this torque causes the rotor to accelerate. 1

Referring now to FIGURE 12, in order to maintain the gyro cage during the filling operation, piston 66 of the caging mechanism is moved to the right prior to filling. Inits extreme position, it bears on a snap ring 78,

coupled to the locking piston 61 and holds the piston so that the inner and outer gimbals are locked. As the filling operation proceeds, the fluid pressure in pressure chamber 65 gradually reaches the pressure in the housing. As the pressure, in pressure chamber 65, reaches system pressure, the net force acting on its rear face is sufficient to overcome the biasing force of the spring so that the lock member 61 will hold the gimbals at caged position. When the unit is entirely pressurized, the piston member 66 is released and moves to the left thus returning to the position in FIGURE 12. The caging mechanism 25 starts operating to uncage the gimbal simultaneously with the release of the fluid under pressure from the gyroscope housing.

Referring now to FIGURE 12, as the fluid pressure in the housing rapidly decreases, there is a gradual decrease in pressure in chamber 65 due to the restricted flow of fluid through passage 64. As the pressure in chamber 65 continues to drop, the bias force of the spring 71 causes the locking member 61 to move to the left. The timing sequence is predetermined so that the gimbal will not be in the uncaged position until the rotor is at its governed speed. At this point member 61 will be in the extreme left hand position. In this position, the caging indicating switch 72 is actuated providing a signal indicating that the gimbals are uncaged. As the gyro rotor 21 comes to speed, the centrifugal force responsive valve spring 100, for example, and its baflle element 102 begin to move across the orifice area 56 thereby restricting the flow of fluid through the orifice. Accordingly, the thrust and acceleration of the rotor are decreased. In the event that the speed of the rotor 21 momentarily exceeds the governed speed determined by the spring element 100, the battle portion 102 moves entirely across the orifice 56 and completely obscures the entire nozzle opening and the gyro fluid flow is cut off. The gyro rotor 21 then tends to lose speed which results in a lessening of the centrifugal force on the spring 100 which in turn causes the valve to open slightly and thus bring the gyro back to governed speed.

The gyro rotor 21 will therefore experience a minute oscillation in speed about the predetermined governed speed which is determined by the spring constant and the r.p.m. desired. This action will continue until the fluid under pressure in rotor cavity 57 is exhausted after which the gyro will coast to a stop. As can be seen from the above description and the drawings the gyroscope made in accordance with the present invention is an inexpensive, self-contained unit. In addition, the gyroscope can achieve operational speed in a relatively short period of time and then maintain the operational speed over a long period of time. The gyroscope, furthermore, is a reliable unit in that it can be tested and retested prior to its use. The only part of the unit that is destroyed in operational test is the fusing link, in the releasing mechanism assembly. In addition, the gyroscope is capable of a relatively long storage life, although the invention has been described as being utilized in a gyroscope it has many other useful applications. By way of example, it may also be used as a self-contained prime mover.

While there have been described, what or at present is considered to be the preferred embodiments of this invention, it will be obvious to those skilled in the art that various changes and modifications may be made therein without departing from the invention, and it is, therefore, aimed in the appended claims to cover all such changes and modifications as fall within the true spirit and scope of the invention.

What is claimed is:

1. In a fluid actuated gyroscope of the type having (a) a hollow rotor arranged to store a fluid under pressure,

(b) a reaction impeller communicating between the interior and exterior of said rotor, and

(c) means for initiating the flow of said fluid through said impeller to cause rotation of said rotor, the improvement comprising a rotor speed governor including (d) a valve member arranged to throttle said fluid flow upon movement of said member away from the axis of rotation of said rotor in response to the centrifugal force caused by rotation about said axis, and

(e) means resiliently urging said member toward said axis and against said centrifugal force.

2. The combination defined in claim 1 in which (a) said means resiliently urging said member includes a spring disposed within said rotor, and

(b) said valve member is mounted on said spring and so positioned as to be urged by centrifugal force into a location blocking the passageway defined by said impeller.

3. The combination defined in claim 2 in which (a) said spring is a leaf spring having one end afiixed to said rotor, and

(b) said valve member is affixed to the other end of said leaf spring.

4. A fluid actuated gyroscope comprising about a rotor axis,

10 (b) a fluid reaction impeller communicating between the interior and exterior of said rotor and oriented to cause rotation of said rotor about said axis in response to the passage of fluid through said impeller, (c) a rotor speed governor comprising (1) a valve member shaped to block said impeller,

(2) means mounting said valve member on said rotor,

(3) said mounting means being resilient to movement of said valve member toward and away from said rotor axis,

(4) said mounting means urging said valve member toward said rotor axis against the centrifugal force resulting from rotation of said rotor,

,(5) said centrifugal force urging said valve mem her into blocking engagement with said impeller so as to restrict the flow of fluid through said impeller as the rotational speed of said rotor increases.

References Cited in the file of this patent UNITED STATES PATENTS Allen Oct. 2, 1934 

1. IN A FLUID ACTUATED GYROSCOPE OF THE TYPE HAVING (A) A HOLLOW ROTOR ARRANGED TO STORE A FLUID UNDER PRESSURE, (B) A REACTION IMPELLER COMMUNICATING BETWEEN THE INTERIOR AND EXTERIOR OF SAID ROTOR, AND (C) MEANS FOR INITIATING THE FLOW OF SAID FLUID THROUGH SAID IMPELLER TO CAUSE ROTATION OF SAID ROTOR, THE IMPROVEMENT COMPRISING A ROTOR SPEED GOVERNOR INCLUDING (D) A VALVE MEMBER ARRANGED TO THROTTLE SAID FLUID FLOW UPON MOVEMENT OF SAID MEMBER AWAY FROM THE AXIS OF ROTATION OF SAID ROTOR IN RESPONSE TO THE CENTRIFUGAL FORCE CAUSED BY ROTATION ABOUT SAID AXIS, AND 